Bug 6819

Summary:	duplicate class registration bug
Product:	gcc	Reporter:	oskar
Component:	libgcj	Assignee:	Not yet assigned to anyone <unassigned>
Status:	RESOLVED WONTFIX
Severity:	normal	CC:	bryce, gcc-bugs, java-prs
Priority:	P3
Version:	3.1
Target Milestone:	---
Host:		Target:
Build:		Known to work:
Known to fail:		Last reconfirmed:	2005-09-10 19:33:08
Bug Depends on:	12725
Bug Blocks:

Description oskar 2002-05-26 08:36:00 UTC

This is probably an old and known problem:

If you compile a class that also exists in libgcj into an executable, you'll get an error like this when running the executable:

libgcj failure: Duplicate class registration: org.w3c.dom.Attr
Aborted

Note that the same problem does not occur when running the class with gij.

This (probably) means that if you compile your program with a version of libgcj which doesn't contain class Y, it is not possible to run this program with a newer version of libgcj which does contain class Y. (Granted class Y is compiled into the program in the first place.)

Release:
3.1

Comment 1 Bryce McKinlay 2002-05-27 16:03:41 UTC

From: Bryce McKinlay <bryce@waitaki.otago.ac.nz>
To: gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: libgcj/6819: duplicate class registration bug
Date: Mon, 27 May 2002 16:03:41 +1200

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=6819

 Yes, this is a well known issue. The problem is that if we have 
 duplicated symbols (ie the same symbol representing both old and new 
 versions of a class), it is quite non-deterministic (or at least 
 non-portable) which of them will actually be found and used at runtime 
 by the linker.

 This should be fixable in conjunction with implementing a weaker linking 
 model - this is also needed for strict adherance to Java's binary 
 compatibility spec, and would allow us to do cool things like link 
 compiled classes against interpreted class files, etc.

 Bryce.

Comment 2 Dara Hazeghi 2003-05-27 05:49:21 UTC

Hello,

A good many things have changed since gcc 3.1. Can you confirm whether this bug is still current 
with gcc 3.3? Thanks,

Dara

Comment 3 Andrew Pinski 2003-05-27 14:51:01 UTC

See Dara's question.  But I think this is still a problem, Can you provide a self contained 
example of this, I think I know how to repoduce this but It would be nice for other people.

Comment 4 oskar 2003-05-28 12:57:28 UTC

It seems this bug is fixed in 3.3.

echo >Demo.java 'class Demo { public static void main(String[] args) { File f =
new File(); } }'
mkdir java java/io
echo >java/io/File.java 'public class File { public File() {
System.out.println("hello"); } }'
gcj-3.3 -o Demo java/io/File.java Demo.java --main=Demo
./Demo

That should print 'hello', which it does with 3.3. I haven't tested 3.1 or
earlier with this example though.

Comment 5 oskar 2003-05-28 13:00:56 UTC

I'm sorry, this bug still exists. I forgot to include 'package java.io;' in the
File.java source file in the test above. When you do, you will still get this
error at runtime:

libgcj failure: Duplicate class registration: java.io.File
Aborted

Comment 6 Dara Hazeghi 2003-06-02 03:06:02 UTC

Thanks for the confirmation. Sorry that this one still isn't fixed :-(

Comment 7 Tom Tromey 2003-11-10 07:06:17 UTC

This problem will be fixed by the binary compatibility ABI.
I've marked the dependency on the BC-ABI tracking bug.

Comment 8 Andrew Pinski 2016-09-30 22:50:04 UTC

Closing as won't fix as libgcj (and the java front-end) has been removed from the trunk.